The present invention relates to an improved arrangement containing a controlled deflection roll and a related regulation arrangement or regulator system.
In the commonly assigned copending U.S. application Ser. No. 223,238, filed Jan. 8, 1981, entitled "Controlled Deflection Roll", and since issued as U.S. Pat. No. 4,357,743 on Nov. 1, 1983 there is disclosed a controlled deflection roll which constitutes part of a calender arrangement. This arrangement comprises a controlled deflection roll having a roll shell which is supported by means of support or pressure elements against a roll support or beam, and further contains a regulation arrangement for regulating the position of the roll shell. The position of the roll shell, at least at its two ends, is detected by means of position feelers or sensors and deviations from a set or reference value are processed into two adjustment or positioning magnitudes which act upon and influence the support or pressure elements.
With the arrangement disclosed in the aforementioned patent the roll body is constituted by a hollow cylinder in the interior of which there is arranged the roll support or beam. As the counter element there are used further solid rolls of the calender. However, it is to be specifically understood the present invention is not limited to such type of arrangements. For instance, the roll support or beam can be disposed externally of the roll body which, in turn, can be constructed as a solid or hollow cylinder. Also, there can be provided a plurality of roll supports located in appropriate radial planes, which in each case serve to support or brace pressure or support elements. Equally, the counter rolls can be located in one or a number of planes. As the counter elements there also can be provided bands or also a stationary or movable plane possessing plastic or elastic properties and so forth. In all of these cases which are here mentioned only by way of example and not limitation, it is possible to advantageously employ the teachings of the present invention.
With the heretofore known arrangement there are contemplated different possibilities for inputting the adjustment or positioning signals to the individual support or pressure elements or their controls, as the case may be. Thus, for instance there has been disclosed controlling only a portion of the support elements located near the marginal edge or end of the controlled deflection roll by the signal of the next closest situated position feeler or sensor, whereas the support elements at the central or intermediate zone of the controlled deflection roll are influenced in accordance with the working or operating conditions of the calender.
However, during the operation of a calender arrangement containing such a controlled deflection roll further influencing factors are of significance, as will be explained hereinafter:
If, as in this example, the controlled deflection roll is arranged beneath one or a number of coacting counter rolls which, in turn, are mounted in the calender stand or framework in vertically movable bearings, then the roll shell of the controlled deflection roll initially must take-up the load caused by the force of gravity. Depending upon the construction of the system such can already cause an irregular distribution of the supporting force of the individual support or pressure elements. Furthermore, the support or supporting force of the support or pressure elements must be capable of being adjusted in accordance with the desired base load or mean line force prevailing at the roll nip. Additionally, it is desirable if the machine operator can locally correct the pressing or contact force, since it is possible to thus compensate irregularities of the material which is processed at the calender and which irregularities were possibly caused by upstream located equipment or machines. Finally, there also prevails the possibility that, because of irregular friction conditions present in the machine structure, the position of the roll shell detected by the position feelers or sensors at the one side of the roll shell does not coincide with the position of the roll shell at its other side, and this situation likewise must be compensated for by means of the support or pressure elements.